An electronic surveying equipment comprises an integrated distance and angle measuring instrument, which electro-optically makes measurements towards a target, such as a reflector, for instance a cube corner prism or mirror arrangement or the like, and/or some other kind of active target that the station can lock on. In the recent years such instruments have become modular such that a customer has been able to buy a base equipment and then complete it with extra features later on.
There are known systems having a combination of a surveying equipment and a radio signal position-measuring equipment, below called GPS for simplicity reasons.
U.S. Pat. No. 5,233,357 discloses a terrestrial surveying system comprising an electronic surveying equipment and at least one portable position-measuring unit equipped with a GPS antenna. The disclosed system requires that two persons perform the surveying, one standing at the surveying equipment and the other at the plumb rod having the GPS antenna. The surveying equipment is provided with a computer. The GPS system transmits position data wirelessly to the surveying equipment to be processed in its computer. The person standing at the surveying equipment makes measurements towards the plumb rod having the GPS antenna in the case that the rod is placed where the GPS antenna has a bad or no view of the GPS satellites.